Stereoselective glycosylations of a family of 6-deoxy-1,2-glycals generated by catalytic alkynol cycloisomerization
Stereoselective glycosylations of a family of 6-deoxy-1,2-glycals generated by catalytic alkynol cycloisomerization
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DOI：
10.1021/ja994229u
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发表时间：
2000-05-10
影响因子：
15
通讯作者：
Díaz, Y
中科院分区：
文献类型：
--
作者：
McDonald, FE;Reddy, KS;Díaz, Y
在叔胺（三乙胺或DABCO）和高度官能化的末端炔醇的存在下，0.25当量的W（CO）（6）的光解催化单步、高产率的环异构化为内环烯醇醚。这种转化对于5-羟基-己炔的每种非对映异构体3，4-双甲硅烷基醚是普遍的，导致6-脱氧-1，2-glycals的每种异构体的对映选择性和非对映选择性合成。立体选择性糖基化也已被证明用于每种糖非对映异构体，并已被应用于D-洋地黄毒糖-β-4-D-洋地黄毒糖糖的制备。
Photolysis of 0.25 equiv of W(CO)(6) in the presence of tertiary amines (triethylamine or DABCO) and highly functionalized terminal alkynyl alcohols catalyzes single-step, high-yield cycloisomerization to endocyclic enol ethers. This transformation is general for each diastereomeric 3,4-bissilyl ether of 5-hydroxyl-hexyne, leading to enantio- and diastereoselective syntheses of each isomer of 6-deoxy-1,2-glycals. Stereoselective glycosylations have also been demonstrated for each glycal diastereomer, and have been applied in the preparation of D-digitoxose-beta-4-D-digitoxose glycal.